1. Field of the Invention
This invention relates to a movable fuse socket support which is adapted to be attached to bus bars. The movable fuse socket support is provided on the underside of its socket plate, which includes a fuse holder, with fastening means cooperating with the bus bar, by which fastening means firm contact is established between a separate contact plate which covers the underside of the fuse holder and the bus bar.
2. Description of the Prior Art
Fuse socket supports are available in two systems. One is the so called Diazed system, and the other is a system alternatively called DO, Dezero or Neozed system. Both systems accommodate fuses of different current ratings. To prevent a fuse of an incorrect rating from being inserted, for instance, a high rating fuse from being inadvertently inserted into a low amperage circuit, a gauge ring is used according to the DO system. The gauge ring is de-energized and functions to accommodate the fuses of the proper rating according to their diameters. In a gauge ring system, the fuse is directly attached to the base contact or, as in the present case, to the current carrying bus bar.
In the Diazed system, a gauge or sizing screw is used to ensure proper selection of fuses. The gauge screw is likewise fuse diameter oriented to the diameter of the base contact, but it also functions as the electrical connection to the base contact of the element, or to the current carrying bus bar. This system requires that the bus bar have threaded bores, or it requires an adapter as an additional connecting member between gauge screw and bus bar.
A movable fuse socket support of the foregoing type is known from German Patent Publication OS No. 21 51 641. In this prior movable fuse socket support, the contact plate has an offset section for a tapped bore to receive a gauge screw. The contact plate and the offset section conform to a specific thickness of the bus bar, so that bus bars of different thicknesses require different contact plates. This is because the bus bar is held on the contact plate by a clip which is rotatably mounted on one side of the socket plate. This results in the further disadvantage that when the movable fuse socket support is detached from the bus bar, at least one screw tightening the side of the clip not attached to the socket plate must be removed. To allow for manufacturing tolerances, the clip must be able to flex so as to achieve sufficient tightening and this leads to permanent deformation of the clip. Moreover, the prior movable fuse socket support is suitable for gauge screw systems only. To use it in connection with gauge ring systems, an additional set of contact plates would be required.